A slideway is a mechanical guide designed to provide a device with a track surface that is stable under load (i.e., minimal deflection) with a consistent finish for constant frictional forces, regardless of the rate of movement along the slideway. Slideways may be used in heavy machine tool applications as well as in various electronic components such as disk drives for computers. Other slideways may be included in automotive shifting mechanisms. In order to prevent stick-slip in slideway applications friction at low speed (hereinafter referred to as “static friction”) must be lower than friction at high speed (hereinafter referred to as “dynamic friction”). Surface active agents (friction modifiers, anti-wear additives and extreme-pressure agents) are added to oils to reduce friction. The ability of surface active agents to reduce static friction on metal surfaces is well known. However, in many slideway applications, plastic surfaces are commonly used. Lubricant additives that are effective for metal surfaces may not be effective to reduce friction for plastic surfaces to levels suitable for protecting the plastic surfaces. Accordingly, a need exists for effective lubricant compositions and lubricant additive concentrates that are more suitable for reducing friction in slideways containing plastic components and/or plastic sliding surfaces.
In one embodiment disclosed herein is presented a slideway lubricating additive useful in lubricating oils for slideway applications having a non-metal surface to be lubricated. The lubricating additive includes a metal-free friction modifier; and a metal-free, sulfur-free, phosphorus containing anti-wear/extreme pressure agent. The composition provides a lower coefficient of friction for nonmetal sliding surfaces than for metal sliding surfaces.
In another embodiment is presented a lubricating oil composition containing the slideway lubricating additive. The lubricating oil compositions include a base oil a metal-free friction modifier; and a metal-free, sulfur-free, phosphorus containing anti-wear/extreme pressure agent. The composition provides a lower coefficient of friction for non-metal sliding surfaces than for metal sliding surfaces.
Another embodiment provides a method of lubricating a non-metal surface of a slideway component. The method includes applying a lubricant composition to the slideway component wherein the lubricant contains a base oil; and a metal-free friction modifier; a metal-free, sulfur-free, phosphorus containing anti-wear/extreme pressure agent. The lubricant composition provides a lower coefficient of friction for non-metal sliding surfaces than for metal sliding surfaces.
Since slideways commonly employ various non-metal surfaces, such as plastic and polymeric surfaces, lubricants suitable for friction reduction on non-metal surfaces are critical for successful lubrication of slideways. Lubricants and additive packages for lubricants described herein provide surface active agents that may have similar friction-reducing properties on metal surfaces but dramatically improve friction-reducing properties on non-metal surfaces.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further explanation of the embodiments disclosed and claimed.